BIOL442 Lecture Notes - Lecture 7: Viral Load, Rna Virus, Reassortment
16 Jul 2014
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Document Summary
For a given rna virus species, the genome sequences cluster around a consensus or average sequence, but every genome can be different from every other. Rna-dependent rna and dna polymerases do not have proofreading ability. Error frequencies can be as high as 1 in 10^3 or 10^4 compared to dna-dependent polymerases which are 1 in 106 or lower. Exchange of entire segment between genetically related molecules. Exchange of blocks of nucleotide sequences among genomic molecules within a single virus species. Some require substantial base pair homology, other use base pairing-independent mechanism influenced by secondary structures. Error-prone rna polymerase leads to quasispecies virions being produced. E. g. , 2 different genomes isolated - hong kong, guangdong. Rna sequence shows sars-cov virus is a mosaic with at least 2 evolutionary histories. Polgene is mammalian-like, but m and n are avian-like. Not due to reassortment as genome is unimolecular. Beginning is mammalian (specifically bat) and end is avian.
